(a) Field of the Invention
The present invention relates to a method and an apparatus for transmitting an OFDM signal by applying a discrete Fourier transform-spread.
(b) Description of the Related Art
A discrete Fourier transform-spread orthogonal frequency-division multiplexing (DFT-spread OFDM) (hereinafter, referred to as “DFTS-OFDM”) modulation scheme has been utilized as a main standard technology of a communication system requiring a low power characteristic in that efficiency of a power amplifier may be increased by reducing a fluctuation of instantaneous power using a single-carrier.
Ideally, when a receiver of a wireless communication system based on the DFTS-OFDM modulation scheme receives a signal through a radio channel without a frequency selective characteristic, the receiver may completely recover a transmitted symbol by a DFTS-OFDM demodulator.
However, when the symbol is transmitted at a high transmission rate, the modulated signal configured of a single-carrier has a wideband single-carrier characteristic, such that a signal may be widely spread on time domain. In this case, performance degradation may occur due to inter-symbol interference (ISI) by the frequency selective channel characteristic.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.